Fluorescent tube socket safety lock



Dec. 17, 1968 Filed Feb. 7, 1967 5 Sheets-Sheet l Dec. 17, 1968 J, p, KUNKLE ETAL 3,417,364

FLUORESCENT TUBE SOCKET SAFETY LOCK Filed Feb. 7, 1967 3 Sheets-Sheet z Dec. 17, 1968 J. p KUNKLE ETAL 3,417,364

FLUORESCENT TUBE SOCKET SAFETY LOCK Filed Feb. 7. 1967 5 Sheets-Sheet 3 United States Patent F 3,417,364 FLUORESCENT TUBE SOCKET SAFETY LOCK John Philip Kunkle and William Joseph Garver, Harrisburg, and Harry John Dell, Mechanicsburg, Pa., assignors to AMP Incorporated, Harrisburg, Pa.

Filed Feb. 7, 1967, Ser. No. 614,444 4 Claims. (Cl. 33954) ABSTRACT OF THE DISCLOSURE Means to prevent the accidental removal of a fluorescent tube from its socket. A plug-like member is provided for closing the entry port through which the tube prongs pass while inserting the tube in its socket.

Cross-references to related applications This application is related to US. application Ser. No. 437,451, filed Mar. 5, 1965, and now Patent Number 3,333,227, by Harry John Dell et al. and having a common assignee with the instant application.

Background of the invention (1) Field of the invention: Receptacles for double ended lamps with additional locking or retaining means.

(2) Description of the prior art: Various devices are known for locking fluorescent tubes in their associated sockets. These devices in general have not enjoyed commercial success, either because they were too expensive to produce or because they were not sufiiciently effective in operation. Some specific examples of prior art locking devices are as follows: US. Patent No. 2,537,161, granted Ian. 9, 1951 to H. E. Seim; U.S. Patent No. 2,661,462,

granted Dec. 1, 1953 to L. J. Sklenar; US. Patent No. 2,850,710, granted Sept. 2, 1958 to M. H. Pardue; and US. Patent No. 3,209,304, granted Sept. 28, 1965 to E. I. McLaughlin.

Summary of the invention Brief description of the drawings FIGURE 1 is a perspective view showing a preferred form of locking device as taught by the present invention;

FIGURE 2 is an enlarged perspective view of the locking device as shown in FIGURE 1;

FIGURE 3 is a front view showing the locking device prior to insertion within the tube socket;

FIGURE 4 is a front view showing the locking device in position within the socket;

FIGURE 5 is a front view showing the locking device in its locked position;

FIGURE 6 is a perspective view of a second form of locking device;

FIGURE 7 is an end view of the locking device shown in FIGURE 6;

FIGURE 8 is an end view similar to FIGURE 7 but showing the locking device in its locked position;

FIGURE 9 is a perspective view of a third form of locking device;

3,417,364 Patented Dec. 17, 1968 FIGURE 10 is a perspective view, of a fourth form of locking device; 7

FIGURE 11 is an end view of the device of FIGURE 10 shown in its unlocked position;

FIGURE 12 is an end view similar to FIGURE 11 and showing the locking device moving into its locked position; and

FIGURE 13 is an end view similar to FIGURE 12 showing the locking device seated in its locked position.

Description ofthe preferred embodiments The attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there are shown and described illustrative embodiments of the invention; it is to be understood, however, that these embodiments are not intended to be exhaustive nor limiting of the invention but are given for purpose of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

Referring first to FIGURES 1 through 5, a preferred form of the present invention is illustrated. Fluorescent lights or tubes such as shown in phantom in FIGURE 1 and indicated at 20 are normally mounted in a pair of socket fixtures. The sockets receive the prongs extending from opposite ends of the tube, the prongs entering the socket 22 through the entry port 24 located at the base of the socket. The prongs extending from the tube make contact with the contact arms 25 positioned inside the socket 22.

A problem connected with the use of fluorescent tubes is that such tubes may become dislodged from their socket fixtures by shocks, jars, or vibrations such as are common in building structures and especially in industrial buildings. Any dislodged fluorescent tubes present an obvious safety hazard to the personnel in the building and therefore it is advantageous to provide a means to insure against the accidental removal of the fluorescent tubes from their associated socket fixtures.

. According to the teachings of the present invention a locking key 26 is provided and is adapted to be inserted within the entry port 24 of the socket. The key 26 is preferably made of a dielectric material so as not' to interfere with the socket contacts or the tube prongs. Key 26 has a head portion 28 conveniently formed for manual grasping and a shank portion 30 extending from and preferably integral with the head portion.

The shank portion 30 of the locking key has a generally quadrilateral periphery with a first pair of sides 32 and 34 being closer together than a second pair of sides 36 and 38. A slot 40 extends completely through the shank portion and is disposed in the faces 32 and 34. Shank portion 30 is so dimensioned that the width of the shank between sides 32 and 34 is less than the width of the entry port 24 of the socket whereas the width of the shank between sides 36 and 38 is greater than the width of the entry port.

In use, the key will be inserted into a socket as shown in FIGURE 3. The fluourescent tube will, of course, be mounted within the socket prior to use of the locking key. The key will be aligned with the entry port of the socket so that the sides 32 and 34 of the shank 30 will pass through the entry port as seen in FIGURE 4. With the shank portion so located in the socket the key will be rotated within the entry port, such rotation being facilitated by the arced corners 42 located in opposed edges of the shank portion (see FIGURE 2). Rotation of the locking key within the entry port of the socket will cause the sides 36 and 38 of the key to be deformed in a manner as shown in FIGURES 1 and 5. Such deformation of the key will cause frictional engagement between the key and the socket and prevent removal of the key. With the key so positioned the entry port of the socket is blocked so that the fluorescent tube is incapable of being removed.

An alternative locking device is illustrated in FIGURES 6 through 8. A plate-like structure 50 is provided and is adapted to be bolted or otherwise secured to the socket fixture 22. The plate 50 has a pair of hooklike structures 52 extending from opposite edges thereof. A U-shaped member 54 is provided and is preferably formed of a dielectric material. Plate 50 and member 54 may be made as a single piece joined by a hinge such as 55. The distal ends of member 54 are provided with hook means 56 which cooperate with the hooks 52 in a manner to be described. Located along the base portion of member 54 is a key 58 adapted to be inserted within the entry port 24 of the socket 22.

The operation of the embodiment shown in FIGURE 6 is best described with reference to FIGURES 7 and 8 wherein the member 54 is shown in its two extreme positions relative to the socket 22. With a tube positioned in the socket the member 54 is placed as shown in FIGURE 7 with the hooks 56 engaging the hooks 56 engaging the hooks 52 of the plate 50. The hooks 52 and 56 provide a pivotal axis about which the member 54 can swing. Member 54 is moved counterclockwise to the position shown in FIGURE 8 whereat the key 58 will be located within the entry port 24 to block said port and thereby prevent the withdrawal of the tube.

A further embodiment of the invention is shown in FIGURE 9 wherein the member 54 cooperates with a socket 22, the socket differing from the socket 22 previously described in that socket 22 is provided with a pair of integral ears or hooks 60 for cooperating with the hooks 56 on the member 54. The operation of member 54 is identical to that described in connection with FIGURES 6 through 8, the difference being in the manner in which member 54 is pivotally secured to the socket.

In FIGURES 10 through 13 a still further modification of the present invention is illustrated. A socket 22" is provided which is identical to the socket 22 previously described with the exception that the U-shaped member 54 is formed as an integral part of the socket, the member 54' being connected to the socket by the portion 62 which forms the pivotal axis about which member 54 will move relative to the socket. The member 54 would in this case necessarily be formed of the same dielectric material of which the socket is formed. The key 58 formed on the socket 54' will cooperate with the entry port 24" to prevent withdrawal of the fluourescent tube from the socket.

Member 54' will be positioned as shown in FIGURE 11 when a fluorescent tube is to be mounted into the socket 22". With the tube in position the member 54 will be moved as shown in FIGURE 12 in a clockwise direction until the member 54 is positioned as in FIGURE 13 with the key 58' located within the entry port 24" of the socket. The dielectric material of which the member 54' is formed is sufiiciently resilient to permit the flexing of the member as it moves into and out of position.

Changes in construction will occur to those skilled in the are and various apparently diiferent modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

We claim:

1. A locking key for use with fluorescent light socket fixtures and adapted for insertion within the entry port of said socket, said key comprising a shank, a head formed at one end of said shank, finger-gripping means on said head for permitting manual rotation of said key, said shank being elongated and having a generally quadrilateral periphery, a first pair of sides of said shank spaced farther apart than a second pair of sides of said shank, said first pair of sides being spaced farther than the width of said entry port and said second pair of sides being spaced less than the Width of said entry port, and an elongated closed slot extending through said shank and intersecting said second pair of sides to thereby permit movement of said first pair of sides toward and away from each other, said key being freely insertable Within said entry port when said second pair of sides are aligned with said entry port and wherein rotation of said key to thereby align said first pair of sides with said entry port will cause deformation of said sides to thereby lock said key in position.

2. A locking key as set forth in claim 1 wherein said key is formed of a dielectric material.

3. A locking key as set forth in claim 1 wherein one pair of opposed edges of said shank is arced to facilitate rotation of said key.

4. A locking key as set forth in claim 1 wherein said shank has a second end opposite to said one end, said second end being generally quadrilateral and serving as an end for said closed slot.

References Cited UNITED STATES PATENTS 12/1953 Sklenar 33954 9/1958 Pardue 33954 

